This invention relates to a power wire insertion impact tool, and in particular to a battery-powered tool adapted for insertion of conductor wire in connector blocks and the like.
Wire insertion manual impact tools are well known in the art and are commonly used nowadays for the making of connections to terminals on connector blocks in the electronic and telecommunication fields. See, for example, U.S. Pat. No. 4,241,496, whose contents are herein incorporated by reference, as an example of such tools.
Such tools often use an operating mechanism in which a hammer is biased by a compression coil spring to tilt the hammer or another element with respect to the longitudinal axis of the tool. When the hammer or other element is aligned with the axis, the coil spring is released producing the desired impact. Other tools have used a detent mechanism maintaining a spring-biased hammer until the detent is triggered and the kinetic energy of the hammer is transmitted to a blade and in turn to the wire.
Power wire insertion tools are also known. Typically, they are powered by electrical power from a room outlet and employ an electrical solenoid which is operated to provide the desired impact when a trigger is activated. These power tools demand less effort from the user and are often preferred especially when numerous wires have to be inserted.
A problem is that such power tools are less likely to be used in the field where no local power source is readily available. Moreover, such solenoid-operated insertion tools are not easily operated by a battery because the solenoid consumes too much electrical power and thus the battery is quickly exhausted.
An object of the present invention is an improved impact insertion tool.
A further object of the invention is a battery-powered impact insertion tool that consumes less electrical power than the known tools of the solenoid type operated off the common household voltage.
Another object of the invention is a battery-powered insertion tool exhibiting a reasonable lifetime before requiring battery recharging.
Still another object of the invention is a battery-operated insertion tool that is inexpensive to manufacture.
These objects are achieved in accordance with a feature of the present invention by a battery-powered insertion tool that employs an electric motor to implement the impacting function. The electric motor is provided with suitable gearing that reduces its speed but increases its torque. An activator mechanism is employed to convert multiple revolutions of the motor shaft into a stored compressive force that after a predetermined number of shaft revolutions is triggered to release the compressive force to drive a hammer against an insertion blade mounted in the tool.
In accordance with a preferred embodiment of the invention, the activator mechanism comprises axially-aligned cylindrical end cams with generally complementary surfaces that upon rotation of one of the cams axially extends the other cam compressing a power compression spring, and upon encountering a cam lobe the cams abruptly come together releasing the spring delivering the desired impact to the blade.
Another feature is the addition of an impact-force changing feature in the tool that allows a user to change the impact force between a high and a low value.
A further feature is the addition to the tool of means for changing the orientation of the blade during use.